<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    .parent{
      width: 200px;
      height:200px;

      background-color: #ff8500;
    }
    .child{
      width:50px;
      height:50px;
      background-color: darkred;

      /*static 静态定位，默认定位,就是文档流，边偏移无效*/
      position: static;
      left:10px;
      top:10px;
    }

  </style>
</head>
<body>
<div class="parent">
  <div class="child"></div>
</div>
</body>
</html>